//给定一个候选人编号的集合 candidates 和一个目标数 target ，找出 candidates 中所有可以使数字和为 target 的组合。 
//
// candidates 中的每个数字在每个组合中只能使用 一次 。 
//
// 注意：解集不能包含重复的组合。 
//
// 
//
// 示例 1: 
//
// 
//输入: candidates = [10,1,2,7,6,1,5], target = 8,
//输出:
//[
//[1,1,6],
//[1,2,5],
//[1,7],
//[2,6]
//] 
//
// 示例 2: 
//
// 
//输入: candidates = [2,5,2,1,2], target = 5,
//输出:
//[
//[1,2,2],
//[5]
//] 
//
// 
//
// 提示: 
//
// 
// 1 <= candidates.length <= 100 
// 1 <= candidates[i] <= 50 
// 1 <= target <= 30 
// 
// Related Topics 数组 回溯 
// 👍 1103 👎 0

package leetcode.editor.cn;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.Stack;

/**
 * [40]组合总和 II
 */
public class CombinationSumIi {
    public static void main(String[] args) {
        Solution solution = new CombinationSumIi().new Solution();
        int[] candidates = new int[]{10,1,2,7,6,1,5};
        List<List<Integer>> lists = solution.combinationSum2(candidates, 8);
        System.out.println();
    }
    //leetcode submit region begin(Prohibit modification and deletion)
class Solution {
    private List<List<Integer>> result = new ArrayList<>();
    private int target = 0;
    private int[] candidates;

    public List<List<Integer>> combinationSum2(int[] candidates, int target) {
        Arrays.sort(candidates);
        this.candidates = candidates;
        this.target = target;
        backTrack(0, 0, new Stack<>());
        return result;
    }

    private void backTrack(int startIndex, int sum, Stack<Integer> path) {
        if (sum == target) {
            result.add(new ArrayList<>(path));
            return;
        }
        for (int i = startIndex; i < candidates.length; i++) {
            if (i != startIndex && candidates[i] == candidates[i-1]) {
                continue;
            }
            int tempSUM = sum + candidates[i];
            if (tempSUM > target) {
                continue;
            }
            path.push(candidates[i]);
            backTrack(i+1, sum + candidates[i], path);
            path.pop();
        }
    }
}
//leetcode submit region end(Prohibit modification and deletion)

}